Not showing off at home, but take CD's to listen in a store, primarily to listen to speakers. (don't take LP's), you do not know if their TT system is setup correctly, CD will send the same thing everywhere you go.
1. Rebecca Pidgeon's voice, mentioned above, is pure, let's you know right away about highs/mids balance, not much imaging revealed
2. Casandra Wilson's voice tells you a lot more about upper bass and midrange. Blue Light Till Dawn album. Terrific Imaging from fabulous musicians. Solid center image of her voice, verify no frequency variations l to r.
https://en.wikipedia.org/wiki/Blue_Light_%27til_Dawn3. Duet: Enough is Enough (no more tears) by Barbra Streisand and Donna Summer, the blending and distinction of their individual voices is incredible.
https://www.google.com/search?gs_ssp=eJzj4tVP1zc0TDMyM7csK7M0YPQSSM3LL03PUMgsVoCwAJ-YClU&q=enoug... 4. War of the Worlds, incredible range, and specifically to hear Richard Burton's voice. You can readily tell if it's right or wrong.
https://en.wikipedia.org/wiki/Jeff_Wayne%27s_Musical_Version_of_The_War_of_the_Worlds5. Friday Night in San Francisco, 3 World Class Guitarists play together
https://en.wikipedia.org/wiki/Friday_Night_in_San_FranciscoJohn Mc
Best Imaging Test: Side 2, tracks 2 and 3. My LP beats my CD, but you need a CD version to rule out any misalignment of TT, then use it to refine your TT, it is a great help refining anti-skate
6. Eurythmics, Annie Lennox's Voice and Dave Stewart's sound/imaging variations
https://en.wikipedia.org/wiki/Sweet_Dreams_(Are_Made_of_This)7. Andreas Vollenweider, White Winds, A Sonic Feast
https://en.wikipedia.org/wiki/Andreas_Vollenweider